Cutting tool body having tungsten disulfide coating and method for accomplishing same

ABSTRACT

A method of manufacturing a tool body of a cutting tool comprises mechanically shaping the tool body to provide a metal surface on the tool body having a first surface characteristic. Thereafter, the metal surface is chemically treated with a metal reactant to create a relatively soft metal film along the metal surface. This soft metal film is removed via burnishing or other appropriate action to smooth the metal surface. After the surface is smoothed, the metal surface is then roughened to prepare the surface for the receipt of tungsten disulfide. The roughened metal surface is coated with tungsten disulfide. A cutting tool is disclosed that comprises a tool body defining a substantially isotropic surface having pits formed therein, and tungsten disulfide particles filled into the pits.

FIELD OF THE INVENTION

[0001] This invention pertains to cutting tools and more particularly tosurface treatments of cutting tools.

BACKGROUND OF THE INVENTION

[0002] Cutting tools such as drills, taps, reamers, milling tools,broaches, etc. are used to drill, machine, mill, ream, hone or otherwisecut stock material into desired shapes. Such stock materials forworkpieces include steel of various types and hardness, aluminummaterials, and a wide variety other metal and non-metal materials. Oneof the requirements of any cutting tool is that it typically needs to beharder than the workpiece being cut. Therefore, harder materials such ashigh speed steel, carbide and diamond are often the materials of choiceused for cutting tools. Another requirement is that it needs to havesharp cutting edges. Sharp cutting edges are often accomplished withgrinding to provide sharpness for the desired cutting action. Usually,the cutting tools will have flutes to provide a means to evacuate cutchips as they are generated at the cutting edges of the tool.

[0003] There are three different basic categories of cutting tools,including (1) solid material tools; (2) brazed on carbide tools; and (3)indexable tools. Solid material tools are manufactured from one materialsuch as high speed steel or solid carbide. Brazed on carbide toolscomprise solid carbide “cutters” that are brazed onto a tool body of adifferent material, often steel, and typically, but not limited to 4140,4340, H-13 or S-7. Indexable tools comprise a tool body that comprisesone material, typically 4140, 4340, H-13 or S-7, and inserts (also knownas “cutters”) that are usually made of a different material such ascarbide. The inserts or cutters are attached to the cutter body and heldin place usually with screws. With screws, the cutter inserts areremovable such that they can be indexed to provide a different cuttingedge and/or removed and replaced at the appropriate time.

[0004] Carbide material is frequently the material of choice for cuttingtool edges because carbide is less expensive and easier to use thandiamond. Also, carbide is much harder and much more durable than steel,which provides for a much longer tool life. However, carbide costssubstantially more than steel material such that solid carbide cuttingtools are much more expensive than solid steel tools. As a result, acombination of materials is frequently used, such that carbide cuttingtools often comprise a base tool body comprised of less expensive softersteel material and the harder carbide material is confined to thecutting edges.

[0005] In all cutting tools, the cutting edges typically carry thelargest loads and incur the brunt of direct impact loads. In brazed-oncarbide and indexable carbide cutting tools, the hardness of the carbideat the cutting edge therefore vastly extends tool life over conventionalsolid steel tools. However, in these cutting tools, the softer steeltool body can often be a separate source of problems and can greatlylimit tool life as compared with more expensive solid carbide tools. Forexample, wear and erosion can occur on the surface of tool body, surfacegalling can occur on the contact diameter of the tool as well as theflutes. Tool body wear can occur behind the cutting edge as result ofchip engagement. Among other things, these problems can cause poor chipevacuation and chip packing (and thus increased loads), and can alsolimit coolant flow. The inability to quickly evacuate chips andinsufficient coolant flow can limit tool cutting speed. It is recognizedthat the ultimate failure with a tool is excessive heat generation.Excessive heat can result from one or more of the issues above.

[0006] The common prior art attempts at solving these problems hasfocused upon three different variables, cutter geometry, flute geometry,and surface hardness of the steel tool body. The cutter geometry can bemodified to alter chip geometry for easier evacuation and to preventgalling. Similarly, the flute geometry can be optimized. However, theoptimization of these variables provides only achieves limited benefits.

[0007] Another common technique that is sometimes employed to attempt toextend cutting tool life is to harden the steel tool body with ahardening operation which is accomplished with heat treatment. Typicalapproaches include a hardening operation of the entire tool body orsurface hardening techniques such as carburizing, nitriding and surfaceflame or induction hardening processes. These heat treatments typicallyimprove tool body hardness which in turn increases durability and wearresistance. However, these operations can add significant extra expense.Further, exposing the cutting tool to heat treatment can relieveinternal tool stress that are created inherently when the tool wasoriginally machined, ground and/or milled, that in turn can cause aslight warping or distortion in the tool. Such distortion or warping cancause an unbalanced loading across the cutting tool during cuttingoperations which can also lead to premature failure.

BRIEF SUMMARY OF THE INVENTION

[0008] The invention provides an improved tungsten disulfide surfacetreatment on cutting tool bodies and method that can provide for muchextended cutting tool life and/or increased cutting speeds, and thatsubstantially reduces the problems associated with surface galling, poorchip evacuation and tool body erosion.

[0009] According to an embodiment of the invention, a method ofmanufacturing a tool body of a cutting tool comprises mechanicallyshaping the tool body of the cutting tool to provide a metal surface onthe tool body having a first surface characteristic. Thereafter, theentire metal surface or selected portion of the metal surface ischemically treated with a metal reactant to create a relatively softmetal film along the metal surface that is removed via burnishing orother appropriate action to smooth the metal surface to a smoothersurface characteristic. After the surface is smoothed, the metal surfaceis then roughened to prepare the surface for the receipt of tungstendisulfide. The roughened metal surface is coated with tungstendisulfide.

[0010] A preferred embodiment of a cutting tool that may be produced bythis process or other suitable process comprises a tool body defining asubstantially isotropic surface having pits formed therein, and tungstendisulfide particles filled into the pits.

[0011] Other aspects, objectives and advantages of the invention willbecome more apparent from the following detailed description when takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIGS. 1, 1a, 1 b, 1 c, and 1 d are schematic representations,shown in sequence, of a method used to provide a tungsten disulfidecoated surface on a metal surface of a cutting tool body, in accordancewith a preferred embodiment of the present invention.

[0013]FIGS. 2, 2a, 2 b, 2 c and 2 d are schematic representations, shownin sequence, of the metal surface of the cutting tool body afterdifferent stages of the method illustrated in FIGS. 1, 1a, 1 b, 1 c, and1 d have been accomplished, respectively. Importantly, FIGS. 2, 2a, 2 b,2 c and 2 d do not depict true cross sections and do not representaccurately dimensional characteristics, but are presented to illustrateand convey the concepts and methods disclosed herein to generate agreater understanding and appreciation of the present invention.

[0014]FIG. 3 is a picture of a microscopic SEM image at 300 power of thesurface of a sample laboratory mount of a chromium/molybdenum alloycommon referred to as 4140 material, hardened and tempered to 30 HRC,having a metal surface that has been subjected to a mechanical shapingoperation, leaving a directional finish on the metal surface.

[0015]FIG. 4 is a picture of a microscopic SEM image at 300 power of thesurface of the sample laboratory mount similar to that shown in FIG. 3after a REM® FERROMIL® chemical smoothing process has been appliedsubsequent to the mechanical shaping operation.

[0016]FIG. 5 is a picture of a microscopic SEM image at 300 power of thesurface of the sample laboratory mount similar to that shown in FIGS. 3and 4 after the laboratory mount was subjected to a blasting operationwith 1200 grit size blast aluminum oxide media at an operational stagesubsequent to the REM® FERROMIL® process to roughen the surface of thesample laboratory mount.

[0017]FIG. 6 is a picture of a microscopic SEM image at 300 power of thesurface of the sample laboratory mount similar to that shown in FIGS.3-5, after the sample laboratory mount was subjected to a high velocityimpingement of tungsten disulfide particles at an operation stagesubsequent to the blasting operation.

DETAILED DESCRIPTION OF THE INVENTION

[0018] The following examples and attached figures disclosed hereinfurther illustrate the invention but, of course, should not be construedas in any way limiting its scope.

[0019] For purposes of illustration, a preferred embodiment of thepresent invention is illustrated and described in association with anindexable cutting tool and more specifically an indexable drill bit 10having a steel tool body 12 and carbide cutter inserts 14 as shown inFIG. 1. The cutter inserts 14 are adapted to be mounted to the tool body12 with screws 16. As is conventional, the tool body 12 includes flutes18 that extend axially along the tool body 12 to facilitate chipremoval. The tool body 12 may also include coolant passageways 20 insome applications to communicate coolant to the cutting edges of theinserts 14. Although a drill bit is shown, it will be appreciated thatthe invention is applicable to all cutting tools including taps,reamers, milling tools, broaches, etc. and other appropriate cuttingtools.

[0020] The tool body 12 is mechanically shaped through a conventionalmilling operation 17 and/or other appropriate shaping operations such assanding, belting drilling, lathing, machining, and/or grindingtechniques. These and any other conventional mechanical engagementtechniques are referred to herein as mechanical shaping. As it relatesto cutting tools, the mechanical operation of milling is often used toform the flutes 18 in the tool body 12. Referring to FIG. 1, this isschematically illustrated where a milling tool 22 is shown mechanicallyshaping the flutes 12 into the tool body 12. The result of this processforms a metal surface 24 along the flutes 12 of the tool body 12.

[0021] As will be readily appreciated by those skilled in the art, it isnot possible to provide a perfectly smooth surface as there is always acertain amount of surface roughness after any work operation isperformed in commercial applications. This is particularly true as itpertains to complex surfaces, such as, for example, flutes 18 of thetool body 12, because only rough mechanical shaping operations typicallyare used to avoid undue labor and expense involved in forming thecomplex shape of most flutes 18. This is opposed to the treatment ofsimpler surfaces that are amenable to further refinement, such as themetal surface 27 on other portions of the tool body 12, such as thecylindrical shank portion, which is typically refined and relativelysmooth due to finer and more refined mechanical shaping operations suchas lathing.

[0022] As such, remaining surface roughness on the metal surface 24 ofthe flutes 12 after a mechanical shaping operation is a common surfacefeature of cutting tools. This is schematically indicated in FIG. 2,which is intended to schematically illustrate surface roughness on themetal surface 24 of one of the flutes 18 remaining after a millingoperation. Variation in surface roughness often occurs as illustrated bythe larger peaks 38 and smaller peaks 38 a, and the defined largervalleys 40 and smaller valleys 40 a between peaks.

[0023] Also for purposes of illustration, FIG. 3 is a picture of amicroscopic SEM image taken at 300 power magnification of a laboratorymount sample 100 after a mechanical shaping operation that shows howdirectional characteristics develop after mechanical shaping. As showntherein, laboratory mount sample 100 has a non-isotropic, directionalcharacteristic due to the direction in which the mechanical shapingoperation engages the laboratory mount sample 100. All mechanicalshaping operations that engage the surface generally parallel to thesurface will leave a directional finish.

[0024] Before turning to further description, it should be noted thatthe designators a-d used for FIGS. 1 and 2 and for reference character24 are meant to indicate the sequential steps and progress of the methodand surface for a preferred embodiment.

[0025] After the tool body is mechanically shaped and the flutes 18 aremilled or otherwise mechanically formed into the tool body 12, the toolbody 12 is subjected to a suitable smoothing operation, which preferablyremoves directional surface characteristics, and more preferablysubstantially removes the directional surface characteristics, in thecomplex surfaces of the tool body. In a preferred embodiment, thesmoothing operation is provided by a combination chemical treatment andburnishing operation 25 (also referred to herein as chemicallysmoothing), e.g., as shown in FIG. 2a, to smooth out the peaks 38, 38 aoccurring across the relatively rough metal surface 24 in the flutes 18and to substantially remove any directionality of the metal surface thatcan result from mechanical shaping operations. For cutting tools,chemically smoothing preferably is conducted without any sharpenedcutting edges on the tool body 12, and in the case of the illustratedindexable cutting tool 10, the cutter inserts 14 are removed for thisoperation to avoid rounding and dulling of the cutting edges of thecutter inserts.

[0026] Chemical smoothing can be performed using any suitable processsuch as, for example, subjecting the cutting tool to a metal reactantand a burnishing substance in an environment of mechanical agitation.For example, as shown FIG. 1a, the tool body 12 is placed in a vibratorybowl 26 containing burnishing pieces 28 and an aqueous solution of metalreactant 30 can be introduced and/or circulated via an inlet pipe 32.Alternatively, a tumbling basket or other suitable agitating mechanismmay be used in alternative embodiments. The vibratory bowl 26 isvibrated by a motor 34 which fluidizes the burnishing pieces 28 andcirculates the aqueous solution of metal reactant 30. During thisvibratory process, the metal surface 24 a is constantly wetted with theaqueous solution of metal reactant 30. The metal reactant 30 is of thetype that reacts with the metal surface 24 a to create a removable thinsoft film 36 over the metal surface 24 a. For example, a metal oxidizingagent that reacts with metal to form a soft metal oxide film may be usedto create a readily removable layer. Although, the entire metal surface24 a will quickly become covered with a layer of soft metal film 36, theaction and impact of the burnishing pieces 28 imparted by the vibratoryaction continuously removes this soft metal film 36. Because theburnishing pieces 28 impact or are naturally most prone to impact andscour the higher peaks and elevated portions 38 rather than valleys 40occurring in the metal surface, the burnishing action tends to impactand remove primarily the soft metal film 36 across the elevated portionsor peaks 38, 38 a (which are immediately rewetted with metal reactant tocreate a new soft removable film across the peaks). This effectivelysmoothes the metal surface 24 a as is shown and substantially removesthe surface directionality that may be imparted by prior mechanicalshaping operations. As a result, the surface roughness of the metalsurface can be virtually eliminated, except for some of the valleys andthe substantially smoothed outline of very large ridges 38 which canoften be created during milling operations of tool body 12 to create theflutes 18.

[0027] Preferably, the burnishing pieces 28 are “non-abrasive” in thatthey are softer than the unreacted metal mass of the tool body 12 butharder than the soft metal film 36 that is formed. Suitable materialsfor the burnishing pieces 28 can include, for example, porcelainmaterials and the like. In some applications, it may be desirable tointroduce abrasive particles into the burnishing media, particularlywhere a very large surface roughness characteristic is present. However,the use of conventional abrasive based media (abrasive to the underlyinghard metal of the tool body 12) are rarely used due to the invasivenessand changes in tool geometry that can occur when such media are used.Suitable burnishing pieces 28 should preferably include pieces that aresmall enough to enter the flutes 18 and contact substantially all of themetal surface 24 a to better ensure that the metal surface 24 a of theflutes 18 are smoothed with this chemical smoothing operation 25.

[0028] Suitable types of materials, chemicals and processes that may beused for the chemical smoothing operation are disclosed in U.S. Pat.Nos. 5,158,629; 5,158,623; 5,051,141; 4,906,327; 4,818,333; 4,705,594;4,491,500; and RE 34,272; all of which are owned by REM® Chemicals, Inc.and all of which are hereby incorporated by reference in theirentireties. The preferred chemicals and processes used for this step ofthe invention are commercially available from REM® Chemicals, Inc.located in Southington, Conn. under the brand names FERROMIL® andMAGALLOY®.

[0029] When practicing the invention using the REM® process andproducts, or other chemical smoothing process and products, it will beappreciated that rate at which the chemical smoothing step proceeds maydepend on a number of factors, which include, for example, the natureand concentration of the chemical reactant, the temperature at which theprocess is performed, the solvents used, the chemical and physicalnature of the tool surface, the nature of the surface roughness, andother variables, which are well known to those having ordinary skill inthe art. From a vibratory machine operator's standpoint, after theappropriate chemical reactants are selected, the reactant/solvent (e.g.,water) ratio and the overall flow rate typically are determined byvibratory machine work zone size. Such variables are addressed, forexample, with FERROMIL® chemistry on ferrous metals. The primaryvariable is the total flow rate of the reactant/solvent (e.g., water)combination. This is recommended to be 0.25 or 32 oz. per cubic foot ofbowl size per hour. Thus a 10 cu. Ft. bowl will require 2.5 gal/hr. oftotal flow per hour. The secondary variable is the chemistry/solvent(e.g., water) ratio. Although suitable concentrations of the reactantcan range from about 1 to about 100% percent, common reactants typicallyare used at concentrations ranging from about 10 to about 50%, and morecommonly from about 20-30% for average load densities. The introductionof this mixture is typically accomplished by the use of two precisionlow-volume pumps. One delivers the proper water volume and the othersupplies the chemistry volume. These are simply “piped” to the liquidinlet of the vibratory machine. From a time standpoint, visual and/ormicroscopic inspection can be done to ascertain how much surfaceroughness remains to determine length of time needed for this operation.Typically, it will be in the range of about 1-3 hours, but certainlyother time periods can be used depending upon the operational parametersand aggressiveness of the operation.

[0030] Preferably, after the chemical smoothing operation 25 (which isconducted with the aqueous solution of metal reagent 30), it may bedesirable to perform a further burnishing operation, e.g., an additionalburnishing 42 in a vibratory bowl 45 or other agitator as shownschematically in FIG. 1b, to remove substantially all of the remainingsoft metal film 36, leaving substantially only the hard metal mass ofthe tool body 12, which is resilient and not readily removable. Anadditional burnishing operation better ensures retention of tungstendisulfide particles. Preferably, the additional burnishing operation 42includes placing the cutting tool body 12 into a second vibratory bowl45 or other agitating mechanism containing burnishing pieces 28 and anon-reactive agent such as, for example, water 44 which may beintroduced and/or circulated via an inlet pipe 46. As described herein,the burnishing pieces 28 preferably are non-abrasive to the metal of thetool body 12 but are abrasive to the soft metal film 36 that formsacross the metal surface 24 b. This burnishing operation 42 preferablyremoves substantially all of the remaining soft metal film 36 withoutcreating additional soft metal film, such that the outer metal surface24 b comprises hard steel.

[0031] The result of chemical smoothing and additional burnishingapplications are schematically shown in FIG. 2, which schematicallyillustrate the metal surface 24 b after the chemical shaping operation25 and after the burnishing operation 42, respectively. In someapplications for very rough milled flutes 18, some outlines of largeridges 38 and valleys 40 may remain although the surface over the ridgesand valleys is substantially smooth and substantially isotropic (e.g.free of most of the ordinary roughness comprising smaller peaks 38 a andvalleys 40 a).

[0032] To further illustrate, FIG. 4 is provided which is a picture of amicroscopic SEM image taken at 300 power magnification of the surface ofthe sample laboratory mount sample 100 after chemical smoothing andburnishing operations. When comparing FIG. 4 (the picture taken aftermechanical shaping but prior to chemical smoothing) and FIG. 3 (thepicture taken after chemical smoothing and burnishing), it can be seenthat the chemical smoothing operation can virtually eliminate most ofthe ridges and the valleys as well as other surface roughness betweenformed ridges and valleys. Further, substantially all surfacedirectionality can be removed, making the surface substantiallyisotropic and substantially smooth.

[0033] After the metal surface 24 b is chemically smoothed andpreferably burnished, the surface 24 is then controllably prepared byroughening (pitting) the metal surface 24 c with formed pockets 48. Theroughening of the chemically smoothed surface can be accomplished by anysuitable method, including, for example, blasting methods which are wellknown to those having ordinary skill in the art. To illustrate thisaspect of the present invention, FIG. 1c schematically depicts ablasting operation 50 where abrasive blast media particles 52 arepneumatically discharged through a blast gun or nozzle 54 and impingedat high velocities against the tool body 12. This roughens the metalsurface 24 c and forms the pits or pockets 48 in the metal surface 24 c.This blasting operation 50 prepares the metal surface 24 c for thereceipt of tungsten disulfide particles 50. Preferably, the surface 24 cis subjected to the blasting to a degree, which is sufficient to preparethe surface for accepting the tungsten disulfide particles, but is notsubjected to excessive blasting that would result in excessiveroughening. A preferred method and apparatus for accomplishing thisaspect of the present invention is disclosed in further detail in thepresent patent applicant's prior application, U.S. patent applicationSer. No. 10/263,477, filed on Oct. 3, 2003, the entire disclosure ofwhich is hereby incorporated by reference.

[0034] According to a preferred preparation method, the parameters ofthe blasting operation 50 are controlled to match the size or depth ofthe pockets 48 to the average size of the tungsten disulfide particles30 such that the pockets 28 have a depth about equal to or smaller thanthe average size of the tungsten disulfide particles 56. Commerciallylaboratory sizes of tungsten disulfide typically have a mean particlesize of between about 0.5 micron to about 5 micron. The inventor hasfound the mean particle size of about 1 micron to provide excellentresults.

[0035] Once the size of the tungsten disulfide particle to be used inthe surface treatment is known, the remainder of the parametersincluding the size of the blast media used to prepare the metal surface24 c and various parameters for the blasting operation 50 can bedetermined using methods that are well within the skill of theordinarily skilled artisan. It will be readily appreciated that thehardness and material characteristics of the tool body 12 being treatedwill affect the operating parameters of the blasting operation.

[0036] Because flutes 18 typically may have a metal surface 24 withrelatively large longitudinally extending ridges 38 and valleys 40 as aresult of the difficulties in milling the flutes due to their complexconfiguration, there is presently no commercially practical method forquantifying roughness characteristics of a fluted surface. This is trueeven after the surface 24 of the flutes 18 is smoothed and renderedsubstantially isotropic after the chemical treatment and burnishingoperation 25. Flutes of different shapes and sizes of cutting tools willalso have substantially different roughness characteristics based uponthe type of mechanical shaping tools and processes used to form theflutes. These issues make it difficult to provide for a consistent wayto quantify and measure the surface roughness using a profolometer assurface readings are likely to have too many discrepancies formeaningful use. Further, organized the larger ridges and valleys thatlongitudinally with the flutes 18 are not generally problematic sincethe flutes do not form an actual bearing or hard contact surface butmerely convey chips longitudinally and parallel to such ridges andvalleys. As a result, the parameters selected for the blast operationcan most efficiently be done without any actual measurement readings ofthe flute surfaces, but may be accomplished using blast parameters thatare known to be successful for other metal surfaces formed on a body ofthe same material or a material of similar hardness.

[0037] On the other hand, quantitative measurements, such asprofolometer readings, may be taken across the cylindrical shank portionof the tool body 12 (or a sample laboratory mount, and example of whichis herein described) which, in contrast to the flutes, is typically verysmooth as a result of lathe turn down and/or more refined mechanicalshaping operations, and even smoother after the application of the REM®process described above. Using profolometer readings, the teachings ofmy prior patent application (application Ser. No. 10/263,477) can beused to optimize parameters, such as media size, for the blast operation50.

[0038] In this regard, four basic parameters that determine the preparedmetal surface profile include blast media particle shape, blast mediaparticle size, blast media particle velocity (which is determinedprimarily by the nozzle characteristic and the operating pressure of theblast machinery, and which can be affected by the feed rate of blastmedia), and angularity of the particle stream in relation to the toolbody 12. In roughening the tool body 12 for receipt of tungstendisulfide particles 56, preferred materials and ranges include:

[0039] a. Blast Media Grit Types: Aluminum Oxide or Silicon Carbide;

[0040] b. Blast Media Grit Sizes: typically greater than 200 grit(preferably greater than 400 grit, and more preferably from about 800 toabout 2400 grit);

[0041] c. Gun Pressure: 50-200 psi; and

[0042] d. Blast media carrier gasses, such as, for example, compressedair, pressurized nitrogen, and the like.

[0043] Preferably, the nozzle of the blast gun should be directedgenerally perpendicular relative to the cutting tool and metal surfacesthereon during blasting operations to avoid imparting directionality onthe surface. When the stream of blast media engages a surfaceperpendicularly, no direction is generated on the surface, whichmaintains the generally isotropic characteristics that are generatedwith the REM® process.

[0044] For purposes of illustration, FIG. 2 schematically illustratesthe result of the surface preparation and roughening step in whichformed pockets 48 are pitted into the metal surface 24 c. Also, toillustrate what typically happens, FIG. 5 is provided which is a pictureof a microscopic SEM image of the laboratory mount sample 100 taken at300 power magnification after the laboratory mount was subjected to ablasting operation with 1200 grit size blast media at an operationalstage subsequent to the REM® FERROMIL® process to roughen the surface ofthe laboratory mount sample 100.

[0045] Once the metal surface 24 c has been blasted to provide theformed pockets 48, the pockets 48 can be filled with tungsten disulfideparticles 56 with a tungsten disulfide coating operation 55 asschematically shown in FIG. 1d. Air blasting may be used to provide forhigh velocity impingement of tungsten disulfide particles 56 over themetal surface 24 and is the preferred method for providing a tungstendisulfide coated metal surface 24 d. The result is a tungsten disulfidelayer 58 across the metal surface 24 d that is about one tungstendisulfide particle thick (e.g. about 1 micron thick if using 1 microndiameter particles). With a substantial number of the pits or pockets 48preferably being dimensioned smaller in size than the tungsten disulfideparticles 56, the tungsten disulfide particles 32 project from theformed pockets 48 to form a sliding surface for external interaction.The tungsten disulfide layer 58 effectively covers and provides a smoothdry lubrication layer on the metal surface 24 d.

[0046] It has been surprisingly and unexpectedly found that the tungstendisulfide layer 58 prepared in accordance with the present inventionresults in a significant improvement in the ability of chips to slideacross the metal surface 24 d of the flutes 18, minimizing the directcontact between the metal surface 24 d and the chips. This effectivelyprevents surface galling, improves chip evacuation preventing chippacking and prevents wear or erosion behind the cutting edges and thecontact surfaces of the tool, significantly increasing the useful lifeof the tool, without changing critical geometries or dulling the cuttingedges, particularly for indexing tools. The method of the presentinvention, for example, avoids subjecting the cutter inserts 14, whichprovide the sharp cutting edges and have the most critical geometriesare not subjected to the chemical smoothing process (which tends toremove sharp peaks), and also avoids subjecting the cutting inserts toabrasive media blasting operations. Further, the improvement in chipevacuation allows an increase in metal removal rates resulting inincreases in machining productivity. The present inventive process canalso allow cutting tool manufacturers the ability to eliminate costlyheat treatment and nitriding operations, thereby cutting a substantialamount of expense. Of course, if desired, heat treatment of the toolbody and/or hardening techniques may still be done in addition to thefinishing process of the present invention to further enhance tool life.Considering the economics of cutting tool cost and tool life, however,it is anticipated that such heat treatments will probably be done insome limited applications but will not be done in the vast majority ofapplications.

Illustrative Example

[0047] As discussed above, laboratory mount samples 100 have been usedand are shown at various stages in FIGS. 3-6 to illustrate and provide agreater understanding of the invention, and such laboratory mountsamples may be used to develop operating parameters for practicing theinvention. For practical reasons described above (e.g. flutes are spiralshaped or otherwise not flat), meaningful profolometer readings cannotbe readily obtained on the flutes. By using the laboratory mount sample100, meaningful profolometer readings can be obtained to give insightupon what is happening and to attempt to optimize operating parameters.

[0048] Referring to FIGS. 3-6, there are shown laboratory mount samples100 that were ground and polished to an optically flat surface withoutany visible surface irregularities. Material was a medium-alloychrome/molybendium alloy commonly referred to 4140 hardened and temperedto 30 HRC. This material is very similar to commercially available 4340,both of which represent the most common material that is used inindexable and brazed-on carbide tooling.

[0049] Referring to FIG. 3, the results of a mechanical shapingoperation is depicted. To simulate surface roughness similar to millingof the flutes, the laboratory mount sample 100 was contacted on a 12″diameter silicon carbide abrasive paper at 200 rpm for a period of 5seconds. FIG. 3 represents “machined” surface comprised of “peaks andvalleys”. When measured with a profolometer, the resultant Ra readingwas about 15.

[0050]FIG. 4 shows a laboratory mount sample 100 that was then processedwith FERROMIL® chemistry in a 4 cu. Ft. rotary vibratory bowl withnon-abrasive media at a concentration of 25% chemistry/waterconcentration for a period of 90 minutes resulting in a visibleisotropic surface a viewed on an illuminated microscope at 40×. TheResultant Ra after this operation was about 2.5.

[0051]FIG. 5 shows a laboratory mount sample 100 that was then processedby the tungsten disulfide roughening process resulting in roughersurface Ra of about 4.5. The process parameters used include a 1200 gritaluminum oxide media, standard vapor blast gun with an air jet size of0.1875 in. diameter and a nozzle diameter of 0.375 in. with a nozzlepressure of 150 psi, at an engagement distance of 2 in. for a period of1 sec.

[0052]FIG. 6 shows a laboratory mount sample 100 that was then processedby the tungsten disulfide coating process using high velocityimpingement resulting in a surface Ra of 2.5. The process parametersincluded a tungsten disulphide media mean particle size of 1 micron,standard vapor blast gun with an air jet size of 0.1875 in. diameter anda nozzle diameter of 0.375 in. with a nozzle pressure of 150 psi, at anengagement distance of 2 in. for a period of 1 sec.

[0053] All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

[0054] The use of the terms “a” and “an” and “the” and similar referentsin the context of describing the invention (especially in the context ofthe following claims) are to be construed to cover both the singular andthe plural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

[0055] Preferred embodiments of this invention are described herein,including the best mode known to the inventors for carrying out theinvention. Variations of those preferred embodiments may become apparentto those of ordinary skill in the art upon reading the foregoingdescription. The inventors expect skilled artisans to employ suchvariations as appropriate, and the inventors intend for the invention tobe practiced otherwise than as specifically described herein.Accordingly, this invention includes all modifications and equivalentsof the subject matter recited in the claims appended hereto as permittedby applicable law. Moreover, any combination of the above-describedelements in all possible variations thereof is encompassed by theinvention unless otherwise indicated herein or otherwise clearlycontradicted by context.

What is claimed is:
 1. A method of manufacturing and finishing a toolbody of a cutting tool, comprising: mechanically shaping the tool bodyof the cutting tool to provide a metal surface on the tool body with afirst surface characteristic; thereafter chemically treating the metalsurface with a metal reactant to create a relatively soft metal filmalong the metal surface and removing the soft metal film to smooth themetal surface to a second surface characteristic that is smoother thanthe first surface characteristic; thereafter roughening the metalsurface; and coating the roughened metal surface with tungstendisulfide.
 2. The method of claim 1, wherein the step of mechanicallyshaping comprises at least one mechanical operation selected from thegroup consisting of machining, milling, and lathing, wherein the firstsurface characteristic of the metal surface has a directionaldisposition, and wherein the step of chemically treating and removingsubstantially removes the directional disposition leaving the metalsurface with an substantially isotropic finish and thereby providing thesecond surface characteristic.
 3. The method of claim 1, wherein theroughening comprises blasting the metal surface with blast media to formpits in the metal surface.
 4. The method of claim 3, wherein saidtungsten disulfide comprises tungsten disulfide particles, wherein saidcoating comprises impinging tungsten disulfide particles on the metalsurface to fill the pits with tungsten disulfide particles.
 5. Themethod of claim 5, further comprising selecting a blast media size andoperating parameters for the blasting to control the size the pits to besmaller than a size of the tungsten disulfide particles, whereby asubstantial number of the tungsten disulfide particles project outsideof the pits.
 6. The method of claim 3, wherein the blast media has asize of between 200-1800 grit size.
 7. The method of claim 1, whereinthe cutting tool comprises a metallic tool body and a carbide cuttingedge.
 8. The method of claim 1, wherein said coating comprises impingingthe roughened metal surface with tungsten disulfide particles having amean particle size of between about 0.5 and about 3 micron.
 9. Themethod of claim 1, wherein the step chemical treating and removingcomprises placing the tool body in a vibratory bowl having a pluralityof abrasive and/or non-abrasive media particles and the metal oxidizingagent in an aqueous form, and vibrating the bowl to simultaneously formthe metal film with the metal oxidizing agent and remove the film withthe abrasive and/or non-abrasive media particles.
 10. The method ofclaim 9, further comprising burnishing the tool body in a vibratory bowlcontaining a plurality of non-abrasive media particles.
 11. The methodof claim 1, wherein said mechanical shaping comprises milling axiallyextending flutes into the tool body, the flutes defining the metalsurface.
 12. The method of claim 1, further comprising nitriding thetool body to harden the tool body.
 13. The method of claim 1, furthercomprising, mounting cutters to the tool body at a time after thechemically treating so as to prevent erosion of sharpened edges on thecutters.
 14. A method of finishing a metal surface on a tool body of acutting tool, the metal surface having a directional characteristiccreated by a mechanical shaping operation, the method comprising:smoothing the metal surface and removing the directionality on the metalsurface to provide the metal surface with a substantially isotropicsurface characteristic; thereafter pitting the metal surface to formingpits in the isotropic surface; and filling the pits with tungstendisulfide particles.
 15. The method of claim 14, wherein the pittingcomprises blasting the metal surface with blast media to form pits inthe metal surface.
 16. The method of claim 14, wherein said fillingcomprises impinging tungsten disulfide particles on the metal surface tofill the pits with tungsten disulfide particles.
 17. The method of claim15, further comprising selecting a blast media size and operatingparameters for the blasting to control the size the pits to be smallerthan a size of the tungsten disulfide particles, whereby a substantialnumber of the tungsten disulfide particles project outside of the pits.18. The method of claim 17, wherein the blast media has a size ofbetween 200-1800 grit size.
 19. The method of claim 14, wherein thecutting tool comprises a metallic tool body and a carbide cutting edge.20. The method of claim 14, wherein said filling comprises impinging theroughened metal surface with tungsten disulfide particles having a meanparticle size of between about 0.5 and about 3 micron.
 21. The method ofclaim 1, wherein the step smoothing and removing comprises placing thetool body in a vibratory bowl having a plurality of abrasive and/ornon-abrasive media particles and the metal oxidizing agent in an aqueousform, and vibrating the bowl to simultaneously form the metal film withthe metal oxidizing agent and remove the film with the abrasive and/ornon-abrasive media particles.
 22. The method of claim 21, furthercomprising burnishing the tool body in a vibratory bowl containing aplurality of non-abrasive media particles.
 23. The method of claim 14,wherein said tool body comprises axially extending flutes formed intothe tool body, the flutes defining the metal surface.
 24. The method ofclaim 14, further comprising nitriding the tool body to harden the toolbody.
 25. The method of claim 14, further comprising, mounting cuttersto the tool body at a time after the chemically treating so as toprevent erosion of sharpened edges on the cutters.
 26. A method offinishing a metal surface a tool body, comprising: chemically forming asoft metal film on the metal surface; removing the soft metal film tosmooth the metal surface; thereafter impinging the metal surface withblast media to form pits in the metal surface; and impinging the metalsurface with tungsten disulfide particles.
 27. The method of claim 26,wherein said filling comprises impinging tungsten disulfide particles onthe metal surface to fill the pits with tungsten disulfide particles.28. The method of claim 26, further comprising selecting a blast mediasize and operating parameters for the impinging to control the size thepits to be smaller than a size of the tungsten disulfide particles,whereby a substantial number of the tungsten disulfide particles projectoutside of the pits.
 29. The method of claim 26, wherein the blast mediahas a size of between 200-1800 grit size.
 30. The method of claim 26,wherein the cutting tool comprises a metallic tool body and a carbidecutting edge.
 31. The method of claim 26, wherein the tungsten disulfideparticles have a mean particle size of between about 0.5 and about 3micron.
 32. The method of claim 26, wherein the chemically forming andremoving comprise placing the tool body in a vibratory bowl having aplurality of abrasive and/or non-abrasive media particles and the metaloxidizing agent in an aqueous form, and vibrating the bowl tosimultaneously form the metal film with the metal oxidizing agent andremove the film with the abrasive and/or non-abrasive media particles.33. The method of claim 32, further comprising burnishing the tool bodyin a vibratory bowl containing a plurality of non-abrasive mediaparticles.
 34. The method of claim 26, wherein said tool body comprisesaxially extending flutes formed into the tool body, the flutes definingthe metal surface.
 35. The method of claim 26, further comprisinghardening the tool body.
 36. The method of claim 26, further comprisingmounting cutters to the tool body at a time after the chemicallytreating so as to prevent erosion of sharpened edges on the cutters. 37.A cutting tool comprising a tool body defining a substantially isotropicsurface having pits formed therein, and tungsten disulfide particlesfilled into the pits.
 38. The cutting tool of claim 37, furthercomprising cutters formed separate from the tool body, the cutters beingmounted to the tool body.
 39. The cutting tool of claim 38, wherein thecutters comprise carbide material, each cutter providing a cutting edge,and wherein the tool body comprises metallic material, whereby thecutting tool is categorized as a brazed in carbide tool or an indexabletool.
 39. The cutting tool of claim 37, further comprising flutes formedinto the tool body, the flutes being coated with tungsten disulfideparticles.
 40. The cutting tool of claim 37, wherein the pits areselectively sized such that a substantial number of tungsten disulfideparticles project outside of the pits.
 41. The cutting tool of claim 37,wherein the tungsten disulfide particles have a mean size of between .5and 3 micron.
 42. The cutting tool of claim 37, wherein thesubstantially isotropic surface extends substantially over the entiresurface of the tool body.